Over the past 15 years, we have developed, implemented, and tested the efficacy of an intervention program designed to reduce problem behavior and enhance family management skills during the middle-school years. The Adolescent Transitions Program (ATP) is a multitiered, school-based intervention designed to reduce problem behavior by enhancing family management skills and parent involvement. The goal for the proposed research is to empirically refine and improve a comprehensive family-centered prevention strategy for reducing and preventing adolescent substance use and other problem behaviors. It is clear from our previous research and practical experience working in the public-school setting that we need to improve ATP in three critical areas to build on previous significant effects and enhance the potential for future dissemination and large-scale implementation: (a) improve the feasibility of both the universal level and the indicated level of the intervention by broadening the intervention components and systematically embedding these components into the current behavioral support system in the schools; (b) address the transition from middle to high school, with special attention to academic engagement and reduction of deviant peer clustering, and: (c) explicitly incorporate principles of successful interventions with families and young adolescents of diverse ethnic groups into both our universaland indicated models. Finally, a general goal is to develop, test, and refine a set of research-based instruments that facilitate evaluation, training, implementation, and monitoring of intervention fidelity to maximize the potential success of implementation and large-scale dissemination. In the proposed research, we plan to work within 3 different middle schools in Portland, Oregon, with a sample of approximately 540 youth. Families will be assigned randomly to receive either the ATP program or treatment as usual. Within our experimental group, we will refine further our intervention to enhance engagement across different ethnic groups with a new CulturallyEnhanced Family Check-Up. Assessments will be collected for 5 years through the 10th grade. High-school transition planning and intensive interventionefforts will occur in Grades 7-9. The immediate impact of this intervention will be assessed during the 9th- and lOth-gradeyears. We hypothesize that our intervention will reduce the growth of problem behavior and substance use through the enhancement of family management and parent involvement in school.